Oil well intermittent production time adjusting and optimizing method

Abstract

The invention belongs to the technical field of oil field digitization and oil extraction processes, and particularly provides an oil well intermittent production time adjusting and optimizing method which comprises the following steps: establishing a fault diagnosis simplified model of a sucker-rod pump oil extraction system; solving a recursive format of the indicator diagram of each section of the sucker rod string; calculating to obtain an oil well pump indicator diagram; calculating to obtain a pump fullness degree; and calculating the standard deviation of the pump fullness degree, and adjusting the interval according to the standard deviation of the pump fullness degree. The problems that due to the fact that existing initial intermittent production time adjustment is affected by production factors, intermittent production time adjustment is unreasonable, the oil well productivity cannot be improved, and the energy-saving requirement cannot be met are solved. According to the method, the oil well is always produced under the reasonable intermittent production time adjustment, the development effect is improved, and the energy-saving production requirement is met.

Description

Technical Field

[0001] The invention belongs to the technical field of oil field digitization and oil production technology, and in particular relates to a method for adjusting and optimizing the inter-production time of oil wells. Background Art

[0002] Due to its objective conditions, the exploitation cost of low permeability oil fields is often high. How to efficiently and economically develop such oil fields is the unremitting pursuit of petroleum workers. Due to its reservoir conditions, low permeability oil fields have many low-yield and low-efficiency oil wells. During the development of such wells, especially in the late stage of development, it is very easy to cause empty pumping, which can cause the wear of oil well pipes and rods to increase, shorten the pump inspection cycle, increase the cost of downhole operations, and also cause wear of the pumping unit, equipment failure, and increase maintenance costs. At the same time, the reactive power loss is large, which wastes electricity and leads to high cost per ton of oil. Intermittent production is an effective means for the efficient development of this type of wells. At present, most low-yield and low-efficiency wells generally adopt a development method combining manual intermittent or automatic intermittent. Regardless of which intermittent method is used, the initial intermittent production time adjustment is often insufficient. With the extension of mining time, the adjustment of water injection system, and the influence of measures, the problem of unreasonable intermittent adjustment becomes more and more obvious. This requires the exploration of an optimization method for intermittent production time adjustment of oil wells, and the scientific and rational intermittent adjustment through intelligent learning and analysis.

[0003] A Chinese patent with publication number CN106837298A discloses a method for determining the intermittent production time of a low-liquid-production oil well, comprising the following steps: calculating the production capacity Q of the low-liquid-production oil well, then calculating the liquid production Q at the wellhead of the low-liquid-production oil well by a single quantity method, and then calculating the intermittent production time T of the low-liquid-production oil well according to the production capacity Q of the low-liquid-production oil well and the liquid production Q at the wellhead of the low-liquid-production oil well. This document is a method for determining the intermittent production time of a low-liquid-production oil well, in order to accurately, quickly and easily determine the intermittent production time of a low-liquid-production oil well. However, this document does not solve the problem that the intermittent production time adjustment initially formulated in the prior art is unreasonable due to the extension of the production time, the adjustment of the water injection method, the operation of the measures, etc., and the oil well production capacity cannot be improved, and the energy-saving requirements cannot be met. Summary of the invention

[0004] The purpose of the optimization method for adjusting the intermittent production time of oil wells provided by the present invention is to overcome the problem that the intermittent production time adjustment initially formulated in the prior art is unreasonable due to the extension of mining time, adjustment of water injection method, measures and operations, etc., and the intermittent production time adjustment cannot improve the oil well production capacity and cannot meet the energy-saving requirements.

[0005] To this end, the present invention provides a method for adjusting and optimizing the intermittent production time of oil wells, comprising the following steps:

[0006] 1) Establish a simplified fault diagnosis model for the rod pump oil production system;

[0007] 2) Based on the simplified fault diagnosis model of the rod pumping system, the recursive format of the indicator diagram of each section of the sucker rod string is solved;

[0008] 3) Based on the recursive format of the indicator diagrams of each section of the sucker rod string, the oil well pump diagram is calculated;

[0009] 4) Obtain the effective stroke and plunger stroke of the oil well pump from the oil well pump power diagram, and calculate the pump fullness based on the effective stroke and plunger stroke of the pump;

[0010] 5) Calculate the standard deviation of the pump fullness and adjust the production interval according to the standard deviation of the pump fullness.

[0011] Preferably, the simplified fault diagnosis model of the rod pump oil production system in step 1) is Formula (1) and Formula (2), specifically:

[0012] m i =q ri L i (1)

[0013] In formula (1), q ri is the weight of a single long rod of the ith unit, kg / m; L i is the length of the i-th unit, m.

[0014]

[0015] In formula (2), E i is the elastic modulus of the i-th unit material, Pa; A i is the cross-sectional area of ​​the ith unit, m 2 ; q of each unit ri , L i 、E i , A i Same or different.

[0016] Preferably, the recursive format for solving the indicator diagram of each section of the sucker rod string includes the following steps:

[0017] From Hooke's law we know that:

[0018] F i-1 =k i (s i -s i-1 ) (3)

[0019] Where: F i-1 is the spring k i The forces at both ends;

[0020] Solved:

[0021]

[0022] Where: s i is the concentrated mass m i Displacement of the two ends;

[0023] From Newton's second law:

[0024]

[0025] Substituting equation (4) into equation (5) and rearranging it, we get

[0026]

[0027] The formula (4) and formula (6) are unified as:

[0028]

[0029] Formula (7) is the work diagram of each section of the sucker rod string The recursive format of .

[0030] Preferably, the calculation method of the oil well pump diagram is:

[0031] In formula (7), s i-1 =s i-1 (θ), F i-1 =F i-1 (θ), s i =s i (θ) and F i =F i (θ) are all functions of the crank angle θ, and they are expanded into Fourier series:

[0032]

[0033]

[0034]

[0035]

[0036] Substitute the four Fourier series from equation 8) to equation 10) into equation (7), and assume that the crank rotates at a constant speed, N is the number of strokes, min -1 , After finishing, we can get:

[0037]

[0038]

[0039]

[0040] make

[0041]

[0042] have

[0043]

[0044]

[0045]

[0046] Abbreviated as

[0047]

[0048]

[0049]

[0050] Formula (19) is the pump indicator diagram, and Formula (20) and Formula (21) are the coefficients at the pump.

[0051] Preferably, the calculation method of the effective stroke of the pump is as follows: calculate the curvature change of the target point on the pump dynamometer curve, find the two peak points with the largest curvature change in the high load section of the pump dynamometer, where the one with smaller displacement is the fixed valve opening point, and vice versa is the fixed valve closing point; find the two points with the largest curvature change in the low load section, where the one with smaller displacement is the floating valve closing point, and vice versa is the floating valve opening point; calculate the position difference between the fixed valve opening point and the closing point, and the position difference between the floating valve opening point and the closing point, respectively, and select the one with the smaller position difference as the effective stroke, where the position difference between the two is the position difference between the fixed valve opening point and the closing point, and the position difference between the floating valve opening point and the closing point.

[0052] Preferably, the method for calculating the curvature change of the target point on the pump dynamometer curve is:

[0053] Any point P on the pump indicator curve i The curvature K i According to the five adjacent data points: P i-2 (s i-2 ,f i-2 ), P i-1 (s i-1 ,f i-1 ), P i (s i ,f i ), P i+1 (s i+1 ,f i+1 ), Pi+2 (s i+2 ,f i+2 ), then P i The curvature calculation formula of a point is as follows:

[0054]

[0055] In the formula, Δθ i It is the straight line P i-2 P i To the straight line P i P i+2 The directed rotation angle is calculated as follows:

[0056]

[0057] Arc length Δl i The approximate calculation formula is as follows:

[0058]

[0059] Then point P i The curvature change δK i According to P i , P i+1 The curvature K of two points i , K i+1 Calculated by formula (25):

[0060] δK i =|K i+1 -K i | (25).

[0061] Preferably, the plunger stroke is obtained by reading displacement data on a pump dynamometer diagram.

[0062] Preferably, the pump fullness is obtained by the ratio of the pump effective stroke to the plunger stroke.

[0063] Preferably, the method for calculating the standard deviation of the pump fullness is:

[0064] Step 1) Calculate the daily fullness and the average fullness over a period of time

[0065] Daily fullness

[0066] The fullness calculated for the i-th work chart on the Nth day

[0067] Average filling degree during the production period adjustment

[0068] in,

[0069] i——the number of the i-th work image collected every day (i=1,2……j);

[0070] j——the total number of power diagrams collected every day;

[0071] S effi ——Effective stroke of the ith indicator diagram, m;

[0072] S pi —— plunger stroke of the ith indicator diagram, m;

[0073] m——the intermittent production time adjustment period determined according to the oil field mine practice, d.

[0074] Step 2) Calculate the standard deviation of the fullness

[0075] variance

[0076] Standard deviation of fullness

[0077] Preferably, the adjustment of the production time interval according to the standard deviation of the pump fullness is specifically as follows:

[0078] When the standard deviation of the filling degree is less than or equal to 0.1, the production time will not be adjusted;

[0079] When the standard deviation of the filling degree is greater than 0.1, adjust the production time.

[0080] Beneficial effects of the present invention:

[0081] 1. The method for optimizing the adjustment of the intermittent production time of oil wells provided by the present invention establishes a simplified fault diagnosis model for the pumping rod oil production system; on the basis of the simplified fault diagnosis model for the pumping rod oil production system, solves the recursive format of the indicator diagram of each section of the pumping rod column; on the basis of the recursive format of the indicator diagram of each section of the pumping rod column, calculates the oil well pump diagram; obtains the effective stroke and plunger stroke of the oil well pump from the oil well pump diagram, and calculates the pump fullness according to the effective stroke and plunger stroke of the pump; calculates the standard deviation of the pump fullness, and adjusts the intermittent production time according to the standard deviation of the pump fullness. The optimization of the intermittent production time adjustment of the pumping unit is realized, and after continuous optimization and iteration, a closed-loop optimization management of the intermittent production time adjustment is formed, so that such oil wells can always be produced under a more reasonable intermittent production time adjustment, improve the development effect, and meet the energy-saving production requirements.

[0082] 2. In the method for optimizing the adjustment of the inter-well production time provided by the present invention, the curvature change of the target point is calculated by taking the average value of the adjacent five points to improve the calculation accuracy and reduce or eliminate the fluctuation of the curvature change caused by it. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] The present invention will be further described in detail below with reference to the accompanying drawings.

[0084] Figure 1 It is a flow chart of the optimization method for adjusting the production time between oil wells;

[0085] Figure 2 It is a flow chart for dynamic optimization of intermittent adjustment;

[0086] Figure 3 is the fullness-time relationship curve in Example 1;

[0087] Figure 4 This is the fullness-time relationship curve in Example 2. DETAILED DESCRIPTION

[0088] like Figure 1 and Figure 2 As shown, a method for optimizing the time adjustment of oil well production, comprising the following steps:

[0089] 1) Establish a simplified fault diagnosis model for the rod pump oil production system;

[0090] Preferably, the step 1) is a simplified fault diagnosis model for a rod pump oil production system (see Figure 1 ) is formula (1) and formula (2), specifically:

[0091] m i =q ri L i (1)

[0092] In formula (1), q ri is the weight of a single long rod of the ith unit, kg / m; L i is the length of the i-th unit, m.

[0093]

[0094] In formula (2), E i is the elastic modulus of the i-th unit material, Pa; A i is the cross-sectional area of ​​the ith unit, m 2 ; q of each unit ri , L i 、E i , A i Same or different.

[0095] Specifically, Figure 1 A simplified model for fault diagnosis of rod pumping system.

[0096] Assume that the displacement s of the sucker rod string is positive downward and negative upward; the axial force F of the sucker rod string is positive for pulling and negative for pressing. Discretize the entire sucker rod string into M units (when M approaches infinity and the length of the longest unit approaches 0, the final solution approaches the exact solution of the problem), and perform the following equivalent treatment on each unit: remove the bending stiffness of the unit (the lateral pressure between the sucker rod and the oil pipe at various locations in the wellbore caused by the bending stiffness can be considered separately), concentrate the mass of the unit at the node at one end of the unit, and form some concentrated mass m i , the tensile and compressive stiffness k is used between each concentrated mass. i The spring is replaced by a spring. Due to the viscosity of the well fluid, there is a viscous damping force between the sucker rod and the liquid column, and its influence is equivalent to a damping coefficient of c. i In addition, due to the existence of lateral pressure between the sucker rod and the tubing, the sucker rod is also affected by non-viscous friction. Assume that the friction coefficient between the sucker rod and the tubing is μ i This transforms the vibration of a continuous elastic body with infinite degrees of freedom into a vibration with multiple degrees of freedom.

[0097] Considering the viscous damping force and non-viscous friction force on the sucker rod string will make the simplified model very complicated. Since their influence on the effective stroke of the pump is not obvious, they are no longer considered in the following derivation to simplify the calculation.

[0098] Since the spring has no mass, the forces acting on both ends of it are the same, such as: spring k i The force at both ends is F i-1 ; The concentrated mass can be considered as a point mass, so the displacements at both ends can be considered the same, such as: the concentrated mass m i The displacement at both ends is s i . So we have:

[0099] m i =q ri L i (1)

[0100] In the formula, q ri , weight of single long rod of the ith unit, kg / m; L i , the length of the i-th unit, m.

[0101]

[0102] In the formula, E i , elastic modulus of the i-th unit material, Pa; A i , the cross-sectional area of ​​the ith unit, m 2 Here, the q of each unit is ri , L i 、E i , A ican be different, so that the simplified fault diagnosis model of the sucker rod pumping system is applicable to the situation of multi-stage sucker rod strings with different materials.

[0103] 2) Based on the simplified fault diagnosis model of the rod pumping system, the recursive format of the indicator diagram of each section of the sucker rod string is solved;

[0104] Preferably, the step 2) of solving the recursive format of the indicator diagram of each section of the sucker rod string comprises the following steps:

[0105] First consider the spring k i , from Hooke's law:

[0106] F i-1 =k i (s i -s i-1 ) (3)

[0107] Where: F i-1 is the spring k i The forces at both ends;

[0108] Solved:

[0109]

[0110] Where: s i is the concentrated mass m i Displacement of the two ends;

[0111] Consider the concentrated mass m i , from Newton's second law:

[0112]

[0113] Substitute equation (4) into equation (5) and rearrange it,

[0114] have to

[0115]

[0116] The formula (4) and formula (6) are unified as:

[0117]

[0118] Formula (7) is the work diagram of each section of the sucker rod string The recursive format of .

[0119] 3) Based on the recursive format of the indicator diagrams of each section of the sucker rod string, the oil well pump diagram is calculated;

[0120] Preferably, the calculation method of the oil well pump diagram is:

[0121] In formula (7), si-1 =s i-1 (θ), F i-1 =F i-1 (θ), s i =s i (θ) and F i =F i (θ) are all functions of the crank angle θ, and they are expanded into Fourier series:

[0122]

[0123]

[0124]

[0125]

[0126] Substitute the four Fourier series from equation 8) to equation 10) into equation (7), and assume that the crank rotates at a constant speed, N is the number of strokes, min -1 , After finishing, we can get:

[0127]

[0128]

[0129]

[0130] make

[0131]

[0132] have

[0133]

[0134]

[0135]

[0136] Abbreviated as

[0137]

[0138]

[0139]

[0140] Formula (19) is the pump indicator diagram, and Formula (20) and Formula (21) are the coefficients at the pump.

[0141] For the diagnostic model, the displacement function of the suspension point position is s0 = s0 (θ) = -s PR (θ) can be solved by the motion analysis of the pumping unit, and the axial force function F0=F0(θ)=F PR (θ) can be obtained by interpolation based on the displacement function and the measured light rod indicator diagram. By expanding them into Fourier series, the coefficients can be obtained and Then, the coefficient at the pump can be obtained directly and quickly through equations (19), (20) and (21): and Finally, the displacement function s at the pump can be obtained by calculating Fourier series equations (8) to (11): pump (θ)=-s M (θ)=-s M and the axial force function F pump (θ) = F M (θ) = F M , and you can get the pump indicator diagram.

[0142] 4) Obtain the effective stroke and plunger stroke of the oil well pump from the oil well pump power diagram, and calculate the pump fullness based on the effective stroke and plunger stroke of the pump;

[0143] Preferably, the calculation method of the effective stroke of the pump is as follows: calculate the curvature change of the target point on the pump dynamometer curve, find the two peak points with the largest curvature change in the high load section of the pump dynamometer, where the one with smaller displacement is the fixed valve opening point, and vice versa is the fixed valve closing point; find the two points with the largest curvature change in the low load section, where the one with smaller displacement is the floating valve closing point, and vice versa is the floating valve opening point; calculate the position difference between the fixed valve opening point and the closing point, and the position difference between the floating valve opening point and the closing point, respectively, and select the one with the smaller position difference as the effective stroke, where the position difference between the two is the position difference between the fixed valve opening point and the closing point, and the position difference between the floating valve opening point and the closing point.

[0144] Preferably, the method for calculating the curvature change of the target point on the pump dynamometer curve is:

[0145] By analyzing the working principle of the oil well pump and observing the geometric characteristics of the theoretical pump indicator diagram, it can be seen that the curvature at the opening and closing points of the valve in the pump indicator diagram changes greatly, and the opening and closing points of the fixed valve are in the high load section of the upstroke, and the opening and closing points of the floating valve are in the low load section of the downstroke.

[0146] Any point P on the pump indicator curve i The curvature K i According to the five adjacent data points: P i-2 (s i-2 ,f i-2 ), P i-1 (si-1 ,f i-1 ), P i (s i ,f i ), P i+1 (s i+1 ,f i+1 ), P i+2 (s i+2 ,f i+2 ) between the geometric relationship calculation (see Figure 3 ), then P i The curvature calculation formula of a point is as follows:

[0147]

[0148] In the formula, Δθ i It is the straight line P i-2 P i To the straight line P i P i+2 The directed rotation angle is calculated as follows:

[0149]

[0150] Arc length Δl i The approximate calculation formula is as follows:

[0151]

[0152] Then point P i The curvature change δK i According to P i , P i+1 The curvature K of two points i , K i+1 Calculated by formula (25):

[0153] δK i =|K i+1 -K i | (25).

[0154] Preferably, the curvature change of the target point is calculated by taking the average value of the adjacent 5 points. The pump indicator curve is calculated by numerical method, and contains complex frequency components. In actual calculation, in order to reduce or eliminate the fluctuation of curvature change caused by it, the average value of 5 adjacent points is generally used to calculate the curvature change of the middle point. To improve the calculation accuracy. That is, formula (26):

[0155]

[0156] Preferably, the plunger stroke is obtained by reading displacement data on a pump dynamometer diagram.

[0157] Preferably, the pump fullness is obtained by the ratio of the pump effective stroke to the plunger stroke.

[0158] Calculate the standard deviation of the pump fullness and adjust the production interval according to the standard deviation of the pump fullness.

[0159] If the initial intermittent production time is adjusted reasonably, the formation fluid will basically be stable after a period of operation according to this intermittent production time adjustment. If the intermittent production time is adjusted unreasonably or the formation fluid is unstable due to measures, water injection adjustment, natural decline in formation energy, etc., the fullness will fluctuate greatly and show an upward or downward trend. At this time, it is necessary to optimize the intermittent production time adjustment. The specific adjustment period can be determined by each oil field according to its own reservoir conditions. The system optimization method is as follows:

[0160] Step 1) Calculate the daily fullness and the average fullness over a period of time

[0161] Daily fullness

[0162] The fullness calculated for the i-th work chart on the Nth day

[0163] Average filling degree during the production period adjustment

[0164] in,

[0165] i——the number of the i-th work image collected every day (i=1,2……j);

[0166] j——the total number of power diagrams collected every day;

[0167] S effi ——Effective stroke of the ith indicator diagram, m;

[0168] S pi —— plunger stroke of the ith indicator diagram, m;

[0169] m——the intermittent production time adjustment period determined according to the oil field mine practice, d.

[0170] Step 2) Calculate the standard deviation of the fullness

[0171] variance

[0172] Standard deviation of fullness

[0173] If the standard deviation value is smaller, it means that the fluctuation of the filling degree is smaller, the oil well production is more stable, and the interval period setting is more reasonable. Conversely, if the standard deviation exceeds the given allowable range, the interval adjustment needs to be further optimized.

[0174] Preferably, the method of adjusting the production time interval according to the standard deviation of the pump fullness is specifically as follows:

[0175] When the standard deviation of the filling degree is less than or equal to 0.1, the production time will not be adjusted;

[0176] Specifically, if the standard deviation, i.e., the overall fluctuation range of the fullness, is less than or equal to 0.1 (which can be set according to the actual situation on site of the oil field), it is considered that the fluctuation range is small, the liquid production is stable, and no optimization adjustment is made for the intermittent production time adjustment.

[0177] When the standard deviation of the filling degree is greater than 0.1, adjust the production time.

[0178] Specifically, if the standard deviation, that is, the overall fluctuation range of the fullness, is greater than 0.1, it is considered that the fluctuation range is large, the liquid production is not stable, and the intermittent production time adjustment needs to be optimized.

[0179] Preferably, the optimization adjustment comprises the following steps:

[0180] 1) Calculate the standard deviation of fullness;

[0181] 2) When the standard deviation of the filling degree is less than or equal to 0.1, the production time will not be adjusted;

[0182] 3) When the standard deviation of the filling degree is greater than 0.1, the production time is adjusted in two cases: one is when the daily average filling degree change trend is increasing, and the other is when the daily average filling degree change trend is decreasing;

[0183] 4) After step 3) is optimized, run an adjustment cycle time, and judge again according to the above steps, and repeat the process in this way to ensure that the intermittent production time adjustment is scientific and reasonable, thereby ensuring the efficient development of intermittent oil well production.

[0184] a. If the filling degree change trend is increasing, the method to adjust the production time is:

[0185] Method 1: The well-stopping time remains unchanged, and the well-opening time is extended by 20%

[0186] Method 2: Reduce well shutdown time by 20% and keep well start time unchanged

[0187] Method 3: Adjust in steps of 10% of the well stop and start time. If the well stop time is shortened by 10%, the well start time will be extended by 10% (recommended)

[0188] b. If the filling degree trend is decreasing, the method to adjust the production time is:

[0189] Method 1: Extend the well stop time by 20% and keep the well start time unchanged

[0190] Method 2: The well-opening time is shortened by 20% while the well-stopping time remains unchanged

[0191] Method 3: Adjust in steps of 10% of the well stop and start time. If the well stop time is extended by 10%, the well start time will be shortened by 10% (recommended).

[0192] The pump fullness reflects the formation's fluid supply capacity. A large fullness indicates that the formation has sufficient fluid supply, while a small fullness indicates that the fluid supply is insufficient. The present invention starts with the fullness of the pumping well pump, analyzes its variation degree and trend according to the fullness standard deviation, and iteratively optimizes the change of the well opening and stopping time, thereby ensuring that the intermittent production time adjustment tends to be more reasonable.

[0193] The technical principle of the present invention is:

[0194] The pump fullness is obtained by the ratio of the pump effective stroke to the plunger stroke.

[0195] Firstly, the oil well indicator diagram is obtained by installing load and displacement sensors at the wellhead. Then, the oil well pump diagram is calculated according to the established mathematical model (simplified fault diagnosis model of rod pump oil production system). The effective stroke of the pump and the plunger stroke are obtained from the pump diagram.

[0196] The present invention optimizes the adjustment of the intermittent production time of the oil pumping units, and through continuous optimization iterations, forms a closed-loop optimization management of the intermittent production time adjustment, so that the intermittent production time adjustment is generally performed within a reasonable range, ensuring that the oil well production is not affected or even improved or more energy-efficient.

[0197] Embodiment 1:

[0198] A well has low liquid volume and adopts intermittent production adjustment (21 hours on and 3 hours off). The daily fullness of the well can be calculated from the daily acquisition of the indicator diagram. The daily average fullness within 15 days from 2022.12.28 to 2023.1.11 is shown in the following table:

[0199] xxx well daily filling degree data table 1

[0200]

[0201] Average fullness

[0202]

[0203] Standard Deviation

[0204]

[0205] Since the standard deviation σ is less than 0.1, the filling degree changes steadily (see Appendix Figure 2 ), so it is considered that the adjustment of the inter-well production time is reasonable and does not need to be optimized.

[0206] Embodiment 2:

[0207] Due to the low liquid volume, a well adopts intermittent production adjustment (8 hours on and 4 hours off) production. The average daily filling degree within 15 days from 2022.11.18 to 2022.12.2 is shown in the following table:

[0208] xxx well daily filling degree data table 2

[0209]

[0210] Average fullness

[0211]

[0212] Standard Deviation

[0213]

[0214] Since the standard deviation σ is greater than 0.1, the trend of the filling degree is increasing (see Appendix Figure 4 ), so it is believed that the adjustment of the inter-well production time needs to be optimized.

[0215] Adjustment method: Adjust in steps of 10% of the well-opening and shut-down time. The well-opening time is shortened by 10%, and the well-opening time is extended by 10%. After optimization, the intermittent production time is adjusted to 8.8 hours of opening and 3.6 hours of shut-down.

[0216] In the description of the present invention, it should be understood that if any term indicates an orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present invention.

[0217] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A method for optimizing the time adjustment of oil well production, characterized in that: The steps include: 1) Establish a simplified fault diagnosis model for the rod pump oil production system; 2) Based on the simplified fault diagnosis model of the rod pumping system, the recursive format of the indicator diagram of each section of the sucker rod string is solved; 3) Based on the recursive format of the indicator diagrams of each section of the sucker rod string, the oil well pump diagram is calculated; 4) Obtain the effective stroke and plunger stroke of the oil well pump from the oil well pump power diagram, and calculate the pump fullness based on the effective stroke and plunger stroke of the pump; 5) Calculate the standard deviation of the pump fullness and adjust the production interval according to the standard deviation of the pump fullness.

2. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 1, characterized in that: The simplified fault diagnosis model of the rod pump oil production system in step 1) is formula (1) and formula (2), which are specifically: m i =q ri L i (1) In formula (1), q ri is the weight of a single long rod of the ith unit, kg / m; L i is the length of the i-th unit, m. In formula (2), E i is the elastic modulus of the i-th unit material, Pa; A i is the cross-sectional area of ​​the ith unit, m 2 ; q of each unit ri , L i 、E i , A i Same or different.

3. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 2, characterized in that: The recursive format for solving the indicator diagram of each section of the sucker rod string includes the following steps: From Hooke's law we know that: F i-1 =k i (s i -s i-1 ) (3) Where: F i-1 is the spring k i The forces at both ends; Solved: Where: s i is the concentrated mass m i Displacement of the two ends; From Newton's second law: Substitute equation (4) into equation (5) and rearrange it, have to The formula (4) and formula (6) are unified as: Formula (7) is the work diagram of each section of the sucker rod string The recursive format of .

4. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 3, characterized in that: The calculation method of the oil well pump diagram is: In formula (7), s i-1 =s i-1 (θ), F i-1 =F i-1 (θ), s i =s i (θ) and F i =F i (θ) are all functions of the crank angle θ, and they are expanded into Fourier series: Substitute the four Fourier series from equation 8) to equation 10) into equation (7), and assume that the crank rotates at a constant speed, N is the number of strokes, min -1 , After finishing, we can get: make have Abbreviated as Formula (19) is the pump indicator diagram, and Formula (20) and Formula (21) are the coefficients at the pump.

5. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 4, characterized in that: The calculation method of the effective stroke of the pump is as follows: calculate the curvature change of the target point on the pump indicator diagram curve, find the two peak points with the largest curvature change in the high load section of the pump indicator diagram, where the one with the smaller displacement is the fixed valve opening point, and vice versa is the fixed valve closing point; find the two points with the largest curvature change in the low load section, where the one with the smaller displacement is the floating valve closing point, and vice versa is the floating valve opening point; calculate the position difference between the fixed valve opening point and the closing point, and the position difference between the floating valve opening point and the closing point respectively, and select the one with the smaller position difference as the effective stroke, where the position difference between the two is the position difference between the fixed valve opening point and the closing point, and the position difference between the floating valve opening point and the closing point.

6. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 5, characterized in that: The calculation method of the curvature change of the target point on the pump indicator diagram curve is: Any point P on the pump indicator curve i The curvature K i According to the five adjacent data points: P i-2 (s i-2 ,f i-2 ), P i-1 (s i-1 ,f i-1 ), P i (s i ,f i ), P i+1 (s i+1 ,f i+1 ), P i+2 (s i+2 ,f i+2 ), then P i The curvature calculation formula of a point is as follows: In the formula, Δθ i It is the straight line P i-2 P i To the straight line P i P i+2 The directed rotation angle is calculated as follows: Arc length Δl i The approximate calculation formula is as follows: Then point P i The curvature change δK i According to P i , P i+1 The curvature K of two points i , K i+1 Calculated by formula (25): δK i =|K i+1 -K i | (25).

7. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 6, characterized in that: The plunger stroke is obtained by reading the displacement data on the pump dynamometer diagram.

8. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 8, characterized in that: The pump fullness is obtained from the ratio of the pump effective stroke to the plunger stroke.

9. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 8, characterized in that: The method for calculating the standard deviation of the pump fullness is: Step 1) Calculate the daily fullness and the average fullness over a period of time Daily fullness The fullness calculated for the i-th work chart on the Nth day Average filling degree during the production period adjustment in, i——the number of the i-th work image collected every day (i=1,2……j); j——the total number of power diagrams collected every day; S effi ——Effective stroke of the ith indicator diagram, m; S pi —— plunger stroke of the ith indicator diagram, m; m——the intermittent production time adjustment period determined according to the oil field mine practice, d. Step 2) Calculate the standard deviation of the fullness variance Standard deviation of fullness 10. The method for adjusting and optimizing the intermittent production time of oil wells according to claim 9, characterized in that: The specific method of adjusting the intermittent production time according to the standard deviation of the pump fullness is: when the standard deviation of the fullness is less than or equal to 0.1, the intermittent production time is not adjusted; when the standard deviation of the fullness is greater than 0.1, the intermittent production time is adjusted.

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